1. Field of the Invention
The present invention relates to a structure of retaining a Liquid Crystal Display (LCD) device of portable electronic equipment and more particularly, to a retaining structure of an LCD device of portable electronic equipment such as cellular phones, pagers, and so on, which prevents an external mechanical stress from applying to the LCD device.
2. Description of the Prior Art
In recent years, there has been the surging need for portable electronic equipment such as mobile communications apparatuses. In particular, car phones, cellular phones, and pagers, which are intended to utilize the public communications service, have been extensively used by not only enterprises but also individuals.
The mobile communications apparatuses of this sort have been usually used for transmission and reception of voice or audio signals and reception of numerical information. However, more recently, they have been often used for reception of character data for the purpose of using various existing information services and of transmitting and receiving electronic mail (E-mail). Accordingly, to increase the displayable number of characters on the screen of a LCD assembly or device, the display area or screen size of the LCD device tends to become larger and larger.
On the other hand, there has been the successive need for making these portable electronic equipment more lightweight and more compact. Thus, recently, the dimensional ratio of the LCD device to the apparatus itself has been increasing more and more.
Usually, a semiconductor Integrated Circuit (IC) is electrically connected to the LCD device for driving this device and for controlling the display operation of the same. The driver IC is typically incorporated into a Tape Carrier Package (TCP). The TCP comprises a flexible tape, on which specific wiring lines and terminals connected to these lines are formed. The driver IC is mounted on the tape so as to be electrically connected to the wiring lines using bonding wires or the like, and is typically encapsulated by a plastic material. It is typical that the driver IC packaged in the form of the TCP is electrically and mechanically connected to the LCD device by a thermally-compressing bonding method using a so-called heat seal or an Anisotropic Conductive Film (ACF).
Moreover, to prevent the LCD device from being damaged or broken due to some mechanical stress caused by shock or some bending or twisting force applied to the case of the apparatus, the LCD device is positioned at a specific location in the communication apparatus by using a frame member. The frame member has an upper frame part surrounding the periphery of the LCD device, thereby forming a space for the LCD device. The LCD device is fitted into the space and as a result, it can be correctly positioned at the desired location. The frame member to which the LCD device is attached is typically mounted on a specific Printed Wring Board (PWB) having specific circuits required for communication.
When the LCD device and the TCP are mounted on the PWB, for the purpose of compactness, the TCP is bent at a specific position so as to be folded in two, thereby arranging them so that the LCD device is overlapped with the underlying driver IC mounted on the TCP. Thus, the LCD device is located on the frame member and at the same time, the driver IC is located on the PWB below the frame member. Because of this configuration, the frame member needs to have a U-shaped lower frame part to form a space between the frame member and the FWB for receiving the driver IC. Furthermore, the U-shaped lower frame part needs to have an opening for allowing the TCP connected to the LCD device to enter the space for the IC.
FIGS. 1 to 3 show a prior-art frame member used for mounting the LCD device on the PWB in a pager.
As shown in FIGS. 1 to 3, a frame member 140 has a rectangular-plate-shaped main part 144, an upper frame part 141 formed on the upper periphery of the part 144, a lower frame part 142 formed on the lower periphery of the part 144, and four engaging pins 143 extending downward from the lower frame part 142.
The main part 144 is used for supporting the LCD device and the upper frame part 141 is used for positioning the same thereon. In other words, the LCD device is located on the upper flat surface 144e of the main part 144, and is fitted into an upper space S101 formed by the main part 144 and the upper frame part 141.
The upper frame part 141 has four walls 141a, 141b, 141c, and 14ld located respectively on the four upper edges of the main part 144 and perpendicular to the same. The left, rear, and right walls 144b, 144c, and 144d cover entirely the corresponding edges of the main part 141, respectively. However, the front wall 144a has a rectangular opening or window 141e at its middle position, covering only the left and right sides of the edge of the main part 144. Thus, it may be said that the upper frame part 141 has an approximately U-shape. The opening or window 141e is provided for allowing the TCP to enter the space S101 through the front wall 141a. 
Similar to the upper frame part 141, the lower frame part 142 has four walls 142a, 142b, 142c, and 142d located respectively on the four lower edges of the main part 144 and perpendicular to the same. The left, rear, and right walls 142b, 142c, and 142d cover entirely the corresponding edges of the main part 144, respectively. However, the front wall 142a has a rectangular opening or window 142e at its middle position, covering only the left and right sides of the edge of the main part 144. The opening or window 142e is provided for allowing the TCP to enter a lower space S102 formed by the main part 144 and the lower frame part 142 through the front wall 142a, where the space S102 is used for receiving the driver IC mounted on the TCP.
The four engaging pins 143 are used for fixing the frame member 140 onto a specific PWB. The pins 143 are inserted into corresponding openings of the PWB and engaged therewith, thereby fixing the frame member 149 to the PWB.
The frame member 140 is typically made of a plastic or metal.
On the other hand, the LCD device is comprised of two glass plates fixed to be parallel to each other and a liquid crystal material confined in the intervening space between these two plates. Transparent electrodes, which are made of indium tin oxide (ITO), are formed on the inner surface of each of the plates. To electrically connect the electrodes to the TCP, part of the electrodes are exposed from the space.
With the prior-art frame member 140, the following problem occurs. Specifically, the flat main part 144 cannot be directly contacted with the PWB because the lower space S102 needs to be formed by the lower frame part 142. At the same time as this, the whole periphery of the lower frame part 142 is unable to be supported by the PWB due to existence of the window 142e. Accordingly, the mechanical strength of the frame member 140 is insufficient in the vicinity of the window 142e, resulting in a problem that some flexure or deflection tends to be generated in the frame member 140 in the vicinity of the window 142e. 
The flexure or deflection thus generated in the frame member 140 will affect badly the LCD device mounted on the member 140, thereby causing mechanical stress concentration in the LCD device near the window 142e. Because of the above-described configuration of the LCD device along with the mechanical stress concentration, cracks tend to be formed in the LCD device, making the user difficult or unable to see the displayed information on the screen or damaging the LCD device itself.
Accordingly, an object of the present invention is to provide a LCD-device retaining structure of portable electronic equipment that increases the mechanical strength of a frame member for supporting an LCD device with a simple measure.
Another object of the present invention is to provide a LCD-device retaining structure of portable electronic equipment that suppresses any damage of the LCD device such as cracks even if the equipment is subjected to external shock or forces.
Still another object of the present invention is to provide a LCD-device retaining structure of portable electronic equipment that suppresses any breakage and failure of the external terminals of the TCP even if the equipment is subjected to external shock or forces.
The above objects together with others not specifically mentioned will become clear to those skilled in the art from the following description.
A LCD-device retaining structure of portable electronic equipment according to a first aspect of the present invention comprises:
(a) an LCD device;
(b) a first circuit board having a driver IC for driving the LCD device, a first set of terminals electrically connected to the driver IC, and a second set of terminals electrically connected to the driver IC;
the first circuit board being flexible so as to be bent at a flexible position;
the first set of terminals being located near one end of the first circuit board and mechanically and electrically connected to the LCD device;
the second set of terminals being located near the other end of the first circuit board;
the first circuit board having penetrating holes;
(c) a second circuit board having specific circuits for the electronic equipment;
the circuits of the second circuit board being mechanically and electrically connected to the second set of terminals of the first circuit board; and
(d) a frame member having a lower frame part and bosses extending downward;
the LCD device being fixed on an upper face of the frame member;
the lower frame part being contacted with the second circuit board to form a space between the frame member and the second circuit board, thereby fixing the frame member to the second circuit board and covering the second set of terminals of the first circuit board in the space;
the lower frame part having a window for allowing the first circuit board to enter the space through the lower frame part;
the bosses being located near the window of the lower frame part and penetrating the holes of the first circuit board to be contacted with the second circuit board in the space.
With the LCD-device retaining structure according to the first aspect of the present invention, the frame member has the bosses located near the window of the lower frame part, and the bosses penetrate the holes of the first circuit board to be contacted with the second circuit board in the space formed between the frame member and the second circuit board. Accordingly, the mechanical strength of the frame member can be increased with a simple measure. Thus, any damage of the LCD device such as cracks and any breakage and failure of the first terminals of the first circuit board such as a TCP can be suppressed even if the portable equipment is subjected to external shock or forces. This means that any breakage and failure of the external terminals of the TCP can be suppressed even if the equipment is subjected to external shock or forces.
In a preferred embodiment of the structure according to the first aspect, the frame member has an upper frame part formed to surround the LCD device. The upper frame part has a window for allowing the first circuit board to penetrate the upper frame part. The windows of the upper and lower frame parts are located near one side of the frame member. The bosses are arranged along the side of the frame member. In this embodiment, the advantages of the invention is conspicuously exhibited.
In another preferred embodiment of the structure according to the first aspect, the frame member has an opening penetrating the same. The bosses of the frame member are arranged near the window of the lower frame part and the opening. In this embodiment, there is an additional advantage that the weight of the frame member can be decreased without lowering its mechanical strength.
A LCD-device retaining structure of portable electronic equipment according to a second aspect of the present invention comprises:
(a) an LCD device;
(b) a first circuit board having a driver IC for driving the LCD device, a first set of terminals electrically connected to the driver IC, and a second set of terminals electrically connected to the driver IC;
the first circuit board being flexible so as to be bent at a flexible position:
the first set of terminals being located near one end of the first circuit board and mechanically and electrically connected to the LCD device;
the second set of terminals being located near the other end of the first circuit board;
the first circuit board having penetrating holes;
(c) a second circuit board having specific circuits for the electronic equipment;
the circuits of the second circuit board being mechanically and electrically connected to the second set of terminals of the first circuit board; and
(d) a frame member having a lower frame part surrounding the entire periphery of the member;
the LCD device being fixed on an upper face of the frame member;
the lower frame part being contacted with the second circuit board to form a closed space between the frame member and the second circuit board, thereby fixing the frame member to the second circuit board and covering the second set of terminals of the first circuit board in the space;
the lower frame part having a window for allowing the first circuit board to enter the space through the lower frame part;
the frame member being supported by the whole lower frame part.
With the LCD-device retaining structure according to the second aspect of the present invention, the frame member has the lower frame part surrounding the entire periphery of the member and is supported by the second circuit board at its whole periphery. Therefore, even if the bosses described in the structure according to the first aspect are not provided, the same advantages as those in the first aspect can be obtained.
In a preferred embodiment of the structure according to the second aspect, the frame member has an upper frame part formed to surround the LCD device. The upper frame part has a window for allowing the first circuit board to penetrate the upper frame part. The windows of the upper and lower frame parts are located near one side of the frame member. In this embodiment, the advantages of the invention is conspicuously exhibited.